A brief submaximal isometric exercise test 'unmasks' systolic and diastolic masked hypertension

The Role of Exercise Blood Pressure in Hypertension: Measurement, Mechanisms, and Management

ABSTRACT

Hypertension affects one in three adults globally and is the leading modifiable risk factor for cardiovascular disease. Although blood pressure measurements at rest are fundamental to the detection and management of hypertension, abnormal blood pressure responses to exercise, namely, an exaggerated exercise blood pressure (EEBP), can provide additional independent information about current and future hypertension risk. This paper summarizes a symposium entitled, "The Role of Exercise Blood Pressure in Hypertension: Measurement, Mechanisms and Management" included at the 2023 American College of Sports Medicine annual meeting, which presented a timely discussion about the clinical utility of EEBP. Here we will summarize the evidence presented by the speakers including considerations for blood pressure measurement during exercise, an overview of EEBP thresholds and discussion about the value of EEBP during submaximal exercise for the identification and management of hypertension, a summary of the potential physiological mechanisms underpinning an EEBP, and a review of exercise prescription guidelines based on new and emerging evidence as they relate to the American College of Sports Medicine's exercise recommendations for hypertension. We conclude by highlighting areas for future research with the overarching goal of improving the measurement and management of hypertension.

Risk Factors Associated With Exaggerated Blood Pressure Response at the Time of Exercise Treadmill Stress Test

BACKGROUND

Exaggerated blood pressure response (EBPR) to exercise stress testing (EST) may be a marker of future hypertension and carry valuable information for the prediction of cardiovascular events. We sought to evaluate the clinical and resting EST parameters associated with an increased likelihood of EBPR.

METHODS

The records of 14,073 patients (mean age: 55 ± 11 years) without known cardiovascular disease who underwent a treadmill EST were analyzed.

RESULTS

The overall prevalence of arterial hypertension was 44%. A considerable proportion (24%) of patients exhibited EBPR. Multivariate analysis of the entire study population showed that middle-aged individuals (40-60 years old), resting systolic BP > 130 mmHg and/or diastolic BP > 80 mmHg, known arterial hypertension, current cigarette smoking, and family history of premature coronary artery disease are all independent risk factors for EBPR (all P < 0.001). Although the presence of arterial hypertension increased the likelihood of EBPR in the analysis of the entire population, the relevant association in subjects above 60 years old is statistically nonsignificant (P = 0.120). Notably, the pre-test systolic BP > 130 mmHg and/or diastolic BP > 80 mmHg level increased significantly the likelihood of manifesting EBPR in all age categories (<40, 40-60, and >60 years old) independent of hypertension presence and in all hypertensive patients independently of antihypertensive treatment intake (all P < 0.001).

CONCLUSIONS

Considering the diagnostic and prognostic utility of EBPR during treadmill EST the clinical and resting hemodynamic parameters that increase the likelihood of EBPR are targets for interventions and preventive measures to modify lifestyle risk behaviors and reduce hypertension and cardiovascular risk factors in the early stages.

Endothelial dysfunction influences augmented aortic hemodynamic responses to metaboreflex activation in postmenopausal women

PURPOSE

Postmenopausal women experience augmented aortic hemodynamic responses to isometric handgrip (IHG) exercise and metaboreflex activation post-exercise muscle ischemia (PEMI). Relationships between endothelial function brachial artery flow-mediated dilation (FMD) and aortic stiffness carotid-femoral pulse wave velocity (cfPWV) with aortic pulsatile hemodynamics during IHG and PEMI have not been determined. The relationships between aortic hemodynamic responses to PEMI were evaluated.

METHODS

Aortic blood pressure (BP), wave reflection, and pressure of forward (Pf) and backward (Pb) waves were measured using arterial tonometry at rest, IHG at 30% maximal force, and PEMI in 30 (15/group) postmenopausal women with low (≤ 4.5%) and normal (≥ 5.5%) FMD. Hemodynamic responses were analyzed as the change (Δ) from rest to the last minute of IHG and PEMI.

RESULTS

Brachial and aortic systolic BP (SBP) responses to IHG were higher in the low vs normal FMD group (P < 0.05). Aortic SBP (Δ20 ± 8 vs Δ11 ± 7 mmHg), pulse pressure (PP) (Δ12 ± 8 vs Δ6 ± 4 mmHg), augmented pressure (AP) (Δ5 ± 3 vs Δ2 ± 2 mmHg), and Pb (Δ6 ± 4 vs Δ3 ± 2 mmHg) responses to PEMI were greater (P < 0.05) in women with low vs. normal FMD. FMD was negatively correlated with aortic SBP, PP, AP, and Pb (P < 0.05) responses to PEMI. cfPWV was not correlated with responses to PEMI.

CONCLUSION

Endothelial dysfunction relates to augmented aortic pulsatile load during metaboreflex activation, which may increase cardiovascular risk in postmenopausal women.

Clinical practice guidelines for the care of girls and women with Turner syndrome

Turner syndrome (TS) affects 50 per 100 000 females. TS affects multiple organs through all stages of life, necessitating multidisciplinary care. This guideline extends previous ones and includes important new advances, within diagnostics and genetics, estrogen treatment, fertility, co-morbidities, and neurocognition and neuropsychology. Exploratory meetings were held in 2021 in Europe and United States culminating with a consensus meeting in Aarhus, Denmark in June 2023. Prior to this, eight groups addressed important areas in TS care: (1) diagnosis and genetics, (2) growth, (3) puberty and estrogen treatment, (4) cardiovascular health, (5) transition, (6) fertility assessment, monitoring, and counselling, (7) health surveillance for comorbidities throughout the lifespan, and (8) neurocognition and its implications for mental health and well-being. Each group produced proposals for the present guidelines, which were meticulously discussed by the entire group. Four pertinent questions were submitted for formal GRADE (Grading of Recommendations, Assessment, Development and Evaluation) evaluation with systematic review of the literature. The guidelines project was initiated by the European Society for Endocrinology and the Pediatric Endocrine Society, in collaboration with members from the European Society for Pediatric Endocrinology, the European Society of Human Reproduction and Embryology, the European Reference Network on Rare Endocrine Conditions, the Society for Endocrinology, and the European Society of Cardiology, Japanese Society for Pediatric Endocrinology, Australia and New Zealand Society for Pediatric Endocrinology and Diabetes, Latin American Society for Pediatric Endocrinology, Arab Society for Pediatric Endocrinology and Diabetes, and the Asia Pacific Pediatric Endocrine Society. Advocacy groups appointed representatives for pre-meeting discussions and the consensus meeting.

Non-invasive parameters of autonomic function using beat-to-beat cardiovascular variations and arterial stiffness in hypertensive individuals: a systematic review

PURPOSE

Non-invasive, beat-to-beat variations in physiological indices provide an opportunity for more accessible assessment of autonomic dysfunction. The potential association between the changes in these parameters and arterial stiffness in hypertension remains poorly understood. This systematic review aims to investigate the association between non-invasive indicators of autonomic function based on beat-to-beat cardiovascular signals with arterial stiffness in individuals with hypertension.

METHODS

Four electronic databases were searched from inception to June 2022. Studies that investigated non-invasive parameters of arterial stiffness and autonomic function using beat-to-beat cardiovascular signals over a period of > 5min were included. Study quality was assessed using the STROBE criteria. Two authors screened the titles, abstracts, and full texts independently.

RESULTS

Nineteen studies met the inclusion criteria. A comprehensive overview of experimental design for assessing autonomic function in terms of baroreflex sensitivity and beat-to-beat cardiovascular variabilities, as well as arterial stiffness, was presented. Alterations in non-invasive indicators of autonomic function, which included baroreflex sensitivity, beat-to-beat cardiovascular variabilities and hemodynamic changes in response to autonomic challenges, as well as arterial stiffness, were identified in individuals with hypertension. A mixed result was found in terms of the association between non-invasive quantitative autonomic indices and arterial stiffness in hypertensive individuals. Nine out of 12 studies which quantified baroreflex sensitivity revealed a significant association with arterial stiffness parameters. Three studies estimated beat-to-beat heart rate variability and only one study reported a significant relationship with arterial stiffness indices. Three out of five studies which studied beat-to-beat blood pressure variability showed a significant association with arterial structural changes. One study revealed that hemodynamic changes in response to autonomic challenges were significantly correlated with arterial stiffness parameters.

CONCLUSIONS

The current review demonstrated alteration in autonomic function, which encompasses both the sympathetic and parasympathetic modulation of sinus node function and vasomotor tone (derived from beat-to-beat cardiovascular signals) in hypertension, and a significant association between some of these parameters with arterial stiffness. By employing non-invasive measurements to monitor changes in autonomic function and arterial remodeling in individuals with hypertension, we would be able to enhance our ability to identify individuals at high risk of cardiovascular disease. Understanding the intricate relationships among these cardiovascular variability measures and arterial stiffness could contribute toward better individualized treatment for hypertension in the future.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO ID: CRD42022336703. Date of registration: 12/06/2022.

The handgrip test - A historical test for diabetic autonomic neuropathy or a marker of something else?

Cardiovascular autonomic neuropathy (CAN) is a frequent complication of diabetes mellitus and is associated with increased morbidity and mortality in patients with diabetes. Hence, early and correct diagnosis of CAN is crucial. Standard cardiovascular reflex rests (CARTs) have been the gold standard of CAN assessment. Originally, CARTs consisted of five reflex tests, but measuring diastolic blood pressure response to sustained handgrip exercise has no longer been suggested as an established clinical test. Increasing body of evidence suggests that isometric handgrip test should no longer be used for the evaluation of sympathetic dysfunction during cardiovascular autonomic neuropathy assessment in diabetic patients. The associations of isometric handgrip test results with parameters of hypertension and markers of hypertension-related target-organ damage in diabetic and non-diabetic individuals point toward its potential role as a screening tool to identify patients with high cardiovascular risk. The current review summarizes historical view of standard cardiovascular reflex tests and latest data on isometric handgrip test.

Targeting Hypertensive Response to Exercise and the Association of Masked Hypertension With Subclinical Organ Damage: A Mini-Review and Meta-Analysis

BACKGROUND

Emerging evidence suggests that a hypertensive response to exercise (HRE) during dynamic or isometric stress tests assessing cardiac function is predictive of hypertension and cardiovascular events such coronary artery disease, heart failure and stroke. Whether HRE represents a marker of masked hypertension (MH) in individuals with no prior history of hypertension is still unclear. This is also the case for the association between MH and hypertension-mediated organ damage (HMOD) in the HRE setting.

METHODS

We addressed this issue through a review and a meta-analysis of studies providing data on this topic in normotensive individuals undergone both to dynamic or static exercise and to 24-h blood pressure monitoring (ABPM). A systematic search was performed using Pub-Med, OVID, EMBASE and Cochrane library databases from inception up to February 28th 2023.

RESULTS

Six studies including a total of 1,155 untreated clinically normotensive individuals were considered for the review. Data provided by the selected studies can be summarized as follows: (i) HRE is a BP phenotype linked to a high prevalence of MH (27.3% in the pooled population); (ii) MH is, in turn, associated with a greater, consistent likelihood of echocardiographic left ventricular hypertrophy (OR: 4.93, CI: 2.16-12.2, P < 0.0001) and vascular organ damage, as assessed by pulse wave velocity, (SMD: 0.34 ± 0.11, CI: 0.12-0.56, P = 0002).

CONCLUSIONS

On the basis of this, albeit limited, evidence, the diagnostic work-up in individuals with HRE should primarily be addressed to look for MH as well as for markers of HMOD, a highly prevalent alteration in MH.

Physiotherapy Screening for Referral of a Patient with Patent Foramen Ovale Presenting with Neck Pain as Primary Complaint: A Case Report

Neck pain is a common musculoskeletal disorder encountered by physiotherapists. However, it may be the early manifestation of more alarming conditions, such as cardiovascular diseases mimicking musculoskeletal pain. Patent foramen ovale (PFO) is a congenital heart defect consisting of a small opening between the right and the left atrium. A 56-year-old male presented with neck pain and head heaviness as primary complaints. The cardiovascular profile and the behavioral symptoms led the physiotherapist to find an exaggerated blood pressure response during exercise; in addition to subtle neurological signs, this prompted the physiotherapist to make an urgent referral. At the emergency department a PFO was diagnosed. To the best of the authors' knowledge, this is the first case to describe a rare clinical presentation of a PFO presenting neck pain as primary complaint. This case report emphasizes the importance for physiotherapists to be able to triage patients for conditions outside their scope suggestive of further medical investigation.

Masked Hypertension and Exaggerated Blood Pressure Response to Exercise: A Review and Meta-Analysis

Aim: Whether exaggerated blood pressure response (EBPR) to exercise represents a marker of masked hypertension (MH) in individuals with no prior history of hypertension is still unclear. We investigated this issue through a review and a meta-analysis of studies providing data on this association in normotensive individuals undergone both to dynamic or static exercise and to 24 h blood pressure monitoring (ABPM). Design: A systematic search was performed using Pub-Med, OVID, EMBASE, and Cochrane library databases from inception up to 31 December 2022. Studies were identified by using the following search terms: “masked hypertension”, “out-of-office hypertension”, “exercise blood pressure”, “exaggerated blood pressure exercise”, “exercise hypertension”. Results: Nine studies including a total of 387 participants with MH and 406 true normotensive controls were considered. Systolic BP (SBP) and diastolic BP (DBP) at rest were significantly higher in MH individuals than in sustained normotensives: 126.4 ± 1.4/78.5 ± 1.8 versus 124.0 ± 1.4/76.3 ± 1.3 mmHg (SMD: 0.21 ± 0.08, CI: 0.06–0.37, p = 0.007 for SBP; 0.24 ± 0.07, CI: 0.08–0.39, p = 0.002 for DBP). The same was true for BP values at peak exercise: 190.0 ± 9.5/96.8 ± 3.7 versus 173.3 ± 11.0/88.5 ± 1.8 mmHg (SMD 1.02 ± 0.32, CI: 0.39–1.65, p = 0.002 for SBP and 0.97 ± 0.25, CI: 0.47–1.96, p < 0.0001 for DBP). The likelihood of having an EBPR was significantly greater in MH than in their normotensive counterparts (OR: 3.33, CI: 1.83–6.03, p < 0.0001). Conclusions: Our meta-analysis suggests that EBPR reflects an increased risk of MH and that BP measurement during physical exercise aimed to assess cardiovascular health may unmask the presence of MH. This underscores the importance of BP measured in the medical setting at rest and in dynamic conditions in order to identify individuals at high cardiovascular risk due to unrecognized hypertension.

Autonomic Afferent Dysregulation in Atrial Fibrillation

OBJECTIVES

This study sought to evaluate the role of cardiac afferent reflexes in atrial fibrillation (AF).

BACKGROUND

Efferent autonomic tone is not associated with atrial remodeling and AF persistence. However, the role of cardiac afferents is unknown.

METHODS

Individuals with nonpermanent AF (n = 48) were prospectively studied (23 in the in-AF group and 25 in sinus rhythm [SR]) with 12 matched control subjects. We performed: 1) low-level lower body negative pressure (LBNP), which decreases cardiac volume, offloading predominantly cardiac afferent (volume-sensitive) low-pressure baroreceptors; 2) Valsalva reflex (predominantly arterial high-pressure baroreceptors); and 3) isometric handgrip reflex (both baroreceptors). We measured beat-to-beat mean arterial pressure (MAP) and heart rate (HR). LBNP elicits reflex vasoconstriction, estimated using venous occlusion plethysmography-derived forearm blood flow (∝1/vascular resistance), maintaining MAP. To assess reversibility, we repeated LBNP (same day) after 1-hour low-level tragus stimulation (in n = 5 in the in-AF group and n = 10 in the in-SR group) and >6 weeks post-cardioversion (n = 7).

RESULTS

The 3 groups were well matched for age (59 ± 12 years, 83% male), body mass index, and risk factors (P = NS). The in-AF group had higher left atrial volume (P < 0.001) and resting HR (P = 0.01) but similar MAP (P = 0.7). The normal LBNP vasoconstriction (-49 ± 5%) maintaining MAP (control subjects) was attenuated in the in-SR group (-12 ± 9%; P = 0.005) and dysfunctional in the in-AF group (+11 ± 6%; P < 0.001), in which MAP decreased and HR was unchanged. Valsalva was normal throughout. Handgrip MAP response was lowest in the in-AF group (P = 0.01). Interestingly, low-level tragus stimulation and cardioversion improved LBNP vasoconstriction (-48 ± 15%; P = 0.04; and -32 ± 9%; P = 0.02, respectively).

CONCLUSIONS

Cardiac afferent (volume-sensitive) reflexes are abnormal in AF patients during SR and dysfunctional during AF. This could contribute to AF progression, thus explaining "AF begets AF." (Characterisation of Autonomic function in Atrial Fibrillation [AF-AF Study]; ACTRN12619000186156).

The effect of muscle blood flow restriction on hemodynamics, cerebral oxygenation and activation at rest

This study tested the hypothesis that muscle blood flow restriction reduces muscle and cerebral oxygenation, at rest. In 26 healthy males, aged 33±2 yrs, physiological variables were continuously recorded during a 10-min period in two experimental conditions: a) with muscle blood flow restriction through thigh cuffs application inflated at 120 mmHg (With Cuffs, WC) and b) without restriction (No Cuffs, NC). Muscle and cerebral oxygenation were reduced by muscle blood flow restriction as suggested by the increase in both muscle and cerebral deoxygenated hemoglobin (Δ[HHb]; p<0.01) and the decrease of muscle and cerebral oxygenation index (Δ[HbDiff]; p<0.01). Hemodynamic responses were not affected by such muscle blood flow restriction, whereas baroreflex sensitivity was reduced (p=0.009). The perception of leg discomfort was higher (p<0.001) in the WC than in the NC condition. This study suggests that thigh cuffs application inflated at 120 mmHg is an effective method to reduce muscle oxygenation at rest. These changes at the muscular level seem to be sensed by the central nervous system, evoking alterations in cerebral oxygenation and baroreflex sensitivity. Novelty bullets: • Thigh cuffs application inflated at 120 mmHg effectively reduces muscle oxygenation at rest. • Limiting muscle oxygenation appears to reduce cerebral oxygenation, and baroreflex sensitivity, at rest. • Even in healthy subjects, limiting muscle oxygenation, at rest, affects neural integration.

Effect of Electroacupuncture on Stress-induced High Blood Pressure via Autonomic Nervous System in Normotensive Young Adults

Acupuncture, which is widely used as a complementary and alternative medicine, has been expected to be beneficial for the treatment of hypertension. However, the antihypertensive effect of acupuncture is still under debate. In the present study, the blood pressure induced by handgrip stress were evaluated using power spectral frequency analysis and hormone examination. This study, which recruited 6 normotensive participants, was designed as a randomized crossover trial of two interventions; electroacupuncture and sham-electroacupuncture. Intervention was delivered as 5 sessions over 2 consecutive weeks. The first electroacupuncture immediately before handgrip exercise did not affect the rates of increase in blood pressure and heart rate. Also, neither increase in LF/HF ratio, as sympathetic nerve activity, nor decrease in HF value, as parasympathetic nerve activity, by handgrip stress was significantly inhibited by a single intervention of electroacupuncture. In addition, 5 repeated electroacupuncture sessions did not attenuate the elevation of blood pressure after handgrip stress, and did not suppress the increase in LF/HF ratio and decrease in HF value. Also, electroacupuncture did not influence the changes in plasma concentrations of renin, aldosterone, norepinephrine, and epinephrine after handgrip stress. No difference was observed in the rate of change in each parameter after handgrip stress between the electroacupuncture treatment group and the sham-electroacupuncture group. The present study did not show any suppressive effect on stress-induced response of blood pressure as well as sympathetic nerve activity. The obtained findings showed no beneficial effects of acupuncture on hypertension as a standalone therapy, consistent with suggestions by previous systematic reviews and meta-analyses. Research with larger sample sizes or higher-quality randomized controlled trials are expected, and a conclusion on the utility of acupuncture treatment for hypertension should be carefully made.

Diabetic Cardiovascular Autonomic Neuropathy, the Handgrip Test and Ambulatory Blood Pressure Monitoring Parameters: Are There Any Diagnostic Implications?

Cardiovascular autonomic neuropathy (CAN) is a common complication of diabetes mellitus. Cardiovascular reflex tests (CARTs) are the gold standard in the diagnosis of CAN, but the handgrip test is no longer recommended to be performed. Previously, the inverse association between the presence of hypertension and handgrip test abnormality was demonstrated and hypertension as major cause for excessive diastolic blood pressure rise during handgrip testing in diabetic individuals proposed. The aim of the present study is to describe more precisely the association between handgrip test and hypertension by performing ambulatory blood pressure monitoring (ABPM) among diabetic patients. A more comprehensive evaluation of the relationship between cardiovascular autonomic function, hypertension and the handgrip test was targeted using heart rate variability (HRV) analysis. Our study involved 163 patients with diabetes. Cardiovascular autonomic neuropathy was assessed by the CARTs and sustained handgrip test was performed. All patients underwent ABPM and HRV analysis well. CAN was diagnosed in 69 patients. Significant associations were found between the diastolic blood pressure increase in response to handgrip exercise and the 24-h (rho = 0.245, p = 0.003), daytime (rho = 0.230, p = 0.005) and night-time (rho = 0.230, p = 0.006) mean systolic and 24-h diastolic (rho = 0.176, p = 0.034) blood pressure values, systolic blood pressure load (rho = 0.252, p = 0.003) and systolic (rho = 0.236, p = 0.005) and diastolic (rho = 0.165, p = 0.047) hyperbaric impacts. Higher values of ambulatory blood pressure monitoring parameters are associated with greater increases in diastolic blood pressure during isometric handgrip exercise. Diastolic blood pressure elevations during the handgrip test are also correlated, in order to diminished heart rate variability parameters attributable to parasympathetic dysfunction highlighting the pivotal role of sympathetic overactivity in evolving handgrip test results. Our study provides further evidence on the inverse association between handgrip test abnormality and hypertension in diabetic patients.

Impact of age, sex and heart rate variability on the acute cardiovascular response to isometric handgrip exercise

Isometric handgrip exercise (IHG) triggers acute increases in cardiac output to meet the metabolic demands of the active skeletal muscle. An abnormal cardiovascular response to IHG might reflect early stages of cardiovascular disease. In a large community-based cohort, we comprehensively assessed the clinical correlates of acute cardiovascular changes during IHG. In total, 333 randomly recruited subjects (mean age, 53 ± 13 years, 45% women) underwent simultaneous echocardiography and finger applanation tonometry at rest and during 3 min of IHG at 40% maximal handgrip force. We calculated time-domain measures of short-term heart rate variability (HRV) from finger pulse intervals. We assessed the adjusted associations of changes in blood pressure (BP) and echocardiographic indexes with clinical characteristics and HRV measures. During IHG, men presented a stronger absolute increase in heart rate, diastolic BP, left ventricular (LV) volumes and cardiac output than women, even after adjustment for covariables. In adjusted continuous and categorical analyses, age correlated positively with the increase in systolic BP and pulse pressure, but negatively with the increase in LV stroke volume and cardiac output during exercise. After full adjustment, a greater increase in systolic and diastolic BP during exercise was associated with lower absolute real variability (P ≤ 0.026) and root mean square of successive differences (P ≤ 0.032) in pulse intervals at rest. In a general population sample, women presented a weaker cardiovascular response to IHG than men. Older age was associated with greater rise in BP pulsatility and diminished cardiac reserve. Low HRV at rest predicted a higher BP increase during isometric exercise.

Nitric Oxide and Decreases in Resistance Exercise Blood Pressure With Aerobic Exercise Training in Older Individuals

An exaggerated blood pressure response to resistance exercise is a marker of masked hypertension and a risk factor for future essential hypertension. Habitual aerobic exercise decreases systolic blood pressure (SBP) during resistance exercise in older individuals, but the underlying mechanisms have not been explored. This study tested the hypothesis that nitric oxide (NO) mediates a reduction of resistance exercise SBP with aerobic training in older individuals. Normotensive older adults participated in a 6-week program as a part of the aerobic training group (n = 23, exercised for an average of 4.4 d/wk and 59 min/d) or the control group (n = 26, asked not to modify their lifestyle during the experimental period). The aerobic exercise intervention increased plasma concentrations of nitrite/nitrate (NOx, end products of NO) and decreased SBP during a one-hand arm curl exercise at 20% and 40% of one-repetition maximum and brachial-ankle pulse wave velocity (an index of arterial stiffness). In the control group, there were no differences in these measures before and after the experimental period. Changes in plasma NOx concentrations during the study period were correlated with changes in resistance exercise SBP. Stepwise regression revealed that changes in plasma NOx concentrations during the experimental period are a significant factor of changes in resistance exercise SBP, independent of age, sex, and changes in serum lipid profile, maximal oxygen uptake, resting SBP, and other variables. These results suggest that NO is associated with decreases in resistance exercise SBP with aerobic training in older individuals and help us better understand why habitual aerobic exercise prevents cardiovascular disease.